1	Flowers bisexual.		(2)
+	Flowers unisexual (shrubs dioecious).		(31)
2 (1)	Branchlets with spines, prickles, or both.		(3)
+	Branchlets with neither spines nor prickles.		(10)
3 (2)	Flowers 4-20 in racemes more than 2 cm		1 R. horridum
+	Flowers solitary, 2 or 3 in clusters, or in racemes less than 2 cm.		(4)
4 (3)	Style and calyx tube adaxially villous		2 R. reclinatum
+	Style and calyx tube adaxially glabrous.		(5)
5 (4)	Fruit oblong, 2-2.5 cm		3 R. stenocarpum
+	Fruit globose, rarely ellipsoid, 0.8-1.5 cm.		(6)
6 (5)	Spines at nodes slender, basally less than 1 mm in diam.		(7)
+	Spines at nodes robust, basally more than 1 mm in diam.		(8)
7 (6)	Leaf blade glabrous except at vein axils; style divided for ca. 1/2 its length		4 R. aciculare
+	Leaf blade pubescent, some hairs glandular; style entire or only stigma 2-lobed		5 R. fuyunense
8 (6)	Calyx tube cylindric, 7-10 mm		6 R. formosanum
+	Calyx tube campanulate, to 6 mm.		(9)
9 (8)	Style 2-lobed at apex; anthers not exserted		7 R. burejense
+	Style divided for ca. 1/2 its length; anthers exserted		8 R. alpestre
10 (2)	Flowers solitary or 2 per fascicle		9 R. ambiguum
+	Flowers in racemes.		(11)
11 (10)	Shrubs low, creeping, or procumbent, to 40 cm tall, rarely semierect to 1 m tall.		(12)
+	Shrubs erect, usually more than 1 m tall.		(14)
12 (11)	Leaf blade with scattered, sessile, yellow glands abaxially		10 R. procumbens
+	Leaf blade without scattered, sessile, yellow glands abaxially, sometimes with glandular hairs.		(13)
13 (12)	Racemes pendent, lax, (3-)5-7-flowered; calyx purple to red		11 R. triste
+	Racemes erect, dense, 5-15-flowered; calyx yellowish white		12 R. palczewskii
14 (11)	Racemes short, 2- or 3-flowered		13 R. fargesii
+	Racemes (2-)4-30(-40) cm, (4-)8-40(-50)-flowered.		(15)
15 (14)	Calyx tube cylindric, 1.2-1.5 cm		14 R. odoratum
+	Calyx tube campanulate or cupular, or if cylindric then less than 0.7 cm.		(16)
16 (15)	Leaf blade with scattered, sessile, yellow glands abaxially.		(17)
+	Leaf blade without scattered, sessile, yellow glands abaxially, sometimes with glandular hairs.		(18)
17 (16)	Calyx and ovary with scattered, sessile, yellow glands		15 R. nigrum
+	Calyx and ovary without scattered, sessile, yellow glands		16 R. americanum
18 (16)	Calyx lobes reflexed at or soon after anthesis.		(19)
+	Calyx lobes erect or incurved at anthesis.		(23)
19 (18)	Racemes lax, rachis clearly visible at anthesis.		(20)
+	Racemes dense, rachis almost hidden at anthesis.		(21)
20 (19)	Petiole 6-8 cm, leaf lobes acuminate at apex; calyx lobes not ciliate; fruit red, 0.8-1.2 cm		17 R. griffithii
+	Petiole 3-5 cm, leaf lobes obtuse to acute at apex; calyx lobes ciliate; fruit purple-black, 0.5-0.7 cm		18 R. altissimum
21 (19)	Racemes spreading then pendulous, fewer than 30-flowered; calyx purple, without warts at base of calyx tube adaxially		19 R. soulieanum
+	Racemes erect then pendulous, usually more than 30-flowered; calyx green to yellow, with 5 warts at base of calyx tube adaxially.		(22)
22 (21)	Leaf lobes coarsely sharply serrate or doubly serrate at margin, acute or shortly acu-minate at apex; warts on adaxial surface of calyx tube not joined by a raised ring		20 R. mandshuricum
+	Leaf lobes coarsely crenate-serrate or doubly serrate at margin, obtuse or acute at apex; warts on adaxial surface of calyx tube joined by a raised ring		21 R. multiflorum
23 (18)	Calyx lobes ciliate or dentate at margin.		(24)
+	Calyx lobes neither ciliate nor dentate at margin, at most erose.		(27)
24 (23)	Racemes lax, rachis clearly visible at anthesis; calyx tube pelviform, 1-1.5 mm		22 R. pubescens
+	Racemes dense, rachis almost hidden at anthesis; calyx tube campanulate to shortly cylindric, 1.5-3.5 mm.		(25)
25 (24)	Petals not ciliate at margin; leaf blade to 12 × 15 cm, petiole 5-8 cm		23 R. latifolium
+	Petals ciliate at margin; leaf blade to 10 × 10 cm, petiole 2.5-5 cm.		(26)
26 (25)	Leaf blade and raceme rachis stalked glandular; petals subspatulate to flabellate; stamens inserted level with petals		24 R. himalense
+	Leaf blade and raceme rachis not stalked glandular; petals narrowly cuneate to linear; stamens inserted below petals		25 R. meyeri
27 (23)	Racemes initially erect, 2-6 cm, 5-15-flowered; calyx tube pelviform or shallowly cupular, 1-2 mm.		(28)
+	Racemes nodding to pendulous, 5-40 cm, 9-50-flowered; calyx tube campanulate to shortly cylindric, 2-6 mm.		(29)
28 (27)	Calyx green to greenish brown; petals purplish; raceme rachis and pedicels sparsely shortly glandular hairy		26 R. rubrum
+	Calyx yellowish white; petals yellowish; raceme rachis and pedicels pubescent at anthesis, glabrous in fruit		12 R. palczewskii
29 (27)	Racemes lax, 15-40-flowered; pedicels 3-10(-15) mm; calyx tube 4-6 mm; stamens exserted		27 R. longeracemosum
+	Racemes dense, 5-30(-50)-flowered; pedicels absent or very short; calyx tube 2-4 mm; stamens included.		(30)
30 (29)	Buds glabrous, apex obtuse; leaf blade adaxially sparsely coarsely glandular hairy; calyx lobes not incurved, apex obtuse; stamens inserted level with petals		28 R. moupinense
+	Buds puberulent, apex acute; leaf blade adaxially densely pubescent; calyx lobes incurved, apex acute; stamens inserted below petals		29 R. setchuense
31 (1)	Shrubs deciduous, though in leaf for most of year; flowers in subsessile umbels or fascicles, rarely solitary		30 R. fasciculatum
+	Shrubs deciduous, semievergreen, or evergreen; flowers in racemes.		(32)
32 (31)	Shrubs evergreen, rarely semievergreen, unarmed; leaf blade margin entire, rarely 3-lobed near apex.		(33)
+	Shrubs deciduous, unarmed or with 2 small prickles at each node; leaf blade margin lobed.		(37)
33 (32)	Branchlets and petioles glandular bristly; petioles 3-8 mm.		(34)
+	Branchlets glabrous; petioles 0.5-4 cm, glabrous or sparsely glandular hairy.		(35)
34 (33)	Leaf blade narrowly elliptic to sublanceolate, ca. 3 × as long as wide; calyx purplish green, glabrous		31 R. tianquanense
+	Leaf blade elliptic to obovate-elliptic, ca. 2 × as long as wide; calyx greenish white, stalked glandular		32 R. henryi
35 (33)	Leaf blade orbicular to reniform-orbicular, about as long as wide; calyx purple to purplish green		33 R. hunanense
+	Leaf blade obovate to elliptic, longer than wide; calyx greenish white or yellowish green.		(36)
36 (35)	Leaf blade 2-5 × 1.5-3 cm; male racemes erect; fruit 0.8-1.1 × 0.6-0.8 cm		34 R. davidii
+	Leaf blade 5-10 × 2.5-4.5 cm; male racemes pendulous; fruit 1.5-2 × 0.7-1 cm		35 R. laurifolium
37 (32)	Nodes each with 2 small spines; internodes minutely prickly or unarmed.		(38)
+	Nodes and internodes unarmed.		(42)
38 (37)	Petioles pubescent to glandular hairy, rarely glabrescent; leaf blade margin 3-5-lobed.		(39)
+	Petioles glabrous, rarely puberulent; leaf blade margin 3-lobed.		(40)
39 (38)	Female racemes up to 6-flowered; calyx tube 2-3 mm; fruit pubescent then glabrescent		36 R. giraldii
+	Female racemes at least 8-flowered; calyx tube 1.5-2 mm; fruit glabrous		37 R. pulchellum
40 (38)	Shrubs low, to 1 m tall; leaf blade puberulent, remaining so at margin and sometimes abaxially		38 R. saxatile
+	Shrubs erect, to 3 m tall; leaf blade glabrous.		(41)
41 (40)	Petioles 0.5-1 cm; leaf blade 1-1.5 cm; male racemes 7-11-flowered		39 R. glabrifolium
+	Petioles 1-2 cm; leaf blade 1.5-3.5 cm; male racemes 10-15-flowered		40 R. diacanthum
42 (37)	Terminal leaf lobe shorter than or rarely equaling lateral ones, apex obtuse, rarely acute.		(43)
+	Terminal leaf lobe equaling or longer than lateral ones, apex acute, acuminate, or caudate.		(46)
43 (42)	Leaf blade glabrous or margin ciliate, rarely viscid glandular; ovary and fruit glabrous		41 R. heterotrichum
+	Leaf blade pubescent, or viscid or stalked glandular, or both; ovary and young fruit pubescent and glandular pubescent.		(44)
44 (43)	Calyx green, sometimes tinged reddish brown		42 R. kialanum
+	Calyx purple or purplish brown.		(45)
45 (44)	Leaf blade orbicular to reniform-orbicular, pubescent and glandular, lobes coarsely obtusely serrate at margin, obtuse at apex; calyx pubescent and glandular		43 R. orientale
+	Leaf blade broadly ovate, glandular but not pubescent, lobes sharply serrate at margin, obtuse to acute at apex; calyx glabrous, rarely puberulent		44 R. xizangense
46 (42)	Leaf blade to 2 cm, terminal lobe slightly longer than lateral ones.		(47)
+	Leaf blade more than 2 cm, terminal lobe usually much longer than lateral ones.		(49)
47 (46)	Calyx pubescent; fruit black or reddish black		45 R. pseudofasciculatum
+	Calyx glabrous; fruit red.		(48)
48 (47)	Calyx purple; leaf blade glabrous, rarely sparsely glandular hairy adaxially; inflorescences glabrous		46 R. humile
+	Calyx green or yellow-green; leaf blade and inflorescences minutely pubescent and stalked glandular		47 R. glabricalycinum
49 (46)	Calyx hairy or glandular or both.		(50)
+	Calyx glabrous.		(55)
50 (49)	Fruit black.		(51)
+	Fruit yellowish green, red, or reddish brown.		(52)
51 (50)	Calyx green, sometimes tinged reddish brown, tube cupular; fruit sparsely stalked glandular, sometimes hairy		48 R. vilmorinii
+	Calyx dark red or purple, tube saucer-shaped, rarely shallowly cupular; fruit glabrous		49 R. rubrisepalum
52 (50)	Fruit densely villous and stalked glandular.		(53)
+	Fruit glabrous, pubescent, or sparsely stalked glandular.		(54)
53 (52)	Leaf blade 2.5-5 cm, margin acutely serrate or doubly serrate; male racemes lax, 6-7 cm, 10-15-flowered		50 R. franchetii
+	Leaf blade 6-10 cm, margin obtusely dentate or doubly dentate; male racemes dense, 7-15 cm, 15-30-flowered or more		51 R. maximowiczii
54 (52)	Leaf blade 5-9 cm, margin deeply doubly serrate, terminal lobe longer than lateral ones, apex acuminate; calyx reddish brown		52 R. takare
+	Leaf blade 2-5 cm, margin irregularly crenate-dentate or doubly dentate, rarely subentire, terminal lobe subequaling lateral ones; calyx green, sometimes tinged reddish brown		42 R. kialanum
55 (49)	Inflorescences stalked glandular, otherwise glabrous.		(56)
+	Inflorescences hairy and stalked glandular.		(57)
56 (55)	Leaf blade glabrous, rarely sparse ly stalked glandular, terminal lobe acute at apex; calyx green		53 R. komarovii
+	Leaf blade coarsely appressed hairy adaxially, terminal lobe acuminate at apex; calyx yellowish brown		54 R. maximowiczianum
57 (55)	Fruit black.		(58)
+	Fruit red or dark purple.		(60)
58 (57)	Terminal leaf lobe usually less than 2 × as long as lateral ones		55 R. luridum
+	Terminal leaf lobe usually more than 2 × as long as lateral ones.		(59)
59 (58)	Male racemes 1.5-2.5 cm; pedicels 1-2 mm; calyx green, sometimes slightly tinged reddish brown
+	desc needed